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Date:   Wed, 5 Oct 2022 14:37:14 +0200
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Subject: Re: [PATCH v8 00/29] Rework the trip points creation
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From:   Daniel Lezcano <daniel.lezcano@linaro.org>
To:     Marek Szyprowski <m.szyprowski@samsung.com>
Cc:     linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
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        Andy Gross <agross@kernel.org>,
        Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>,
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Hi Marek,

On 03/10/2022 23:18, Daniel Lezcano wrote:

[ ... ]

>> I've tested this v8 patchset after fixing the issue with Exynos TMU with
>> https://lore.kernel.org/all/20221003132943.1383065-1-daniel.lezcano@linaro.org/ 
>>
>> patch and I got the following lockdep warning on all Exynos-based boards:
>>
>>
>> ======================================================
>> WARNING: possible circular locking dependency detected
>> 6.0.0-rc1-00083-ge5c9d117223e #12945 Not tainted
>> ------------------------------------------------------
>> swapper/0/1 is trying to acquire lock:
>> c1ce66b0 (&data->lock#2){+.+.}-{3:3}, at: exynos_get_temp+0x3c/0xc8
>>
>> but task is already holding lock:
>> c2979b94 (&tz->lock){+.+.}-{3:3}, at:
>> thermal_zone_device_update.part.0+0x3c/0x528
>>
>> which lock already depends on the new lock.
> 
> I'm wondering if the problem is not already there and related to 
> data->lock ...
> 
> Doesn't the thermal zone lock already prevent racy access to the data 
> structure?
> 
> Another question: if the sensor clock is disabled after reading it, how 
> does the hardware update the temperature and detect the programed 
> threshold is crossed?

just a gentle ping, as the fix will depend on your answer ;)

Thanks

   -- D.

[ ... ]


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